Air-cooled furnace



March 3, 1931. D. s. JACOBUS AIR COOLED FURNACE Filed June 9 1935 INVENTOR.

lllrl ATTORNEY;

Patented Mar 3, 1931 DAVID S JAMBUS, OF JERSEY CITY,

Application and lube a,

My present invention relates to furnaces,

v particularly those in which it is desirable to cool the furnace walls to maintain the same, and will be best understood from the followf ing. description and the annexed drawing in which is shown a vertical longitudinal section of a steam boiler furnace embodying an il- "lustrative form of my invention.

In the embodiment illustrated, the furnace chamber 10 is formed as usual with vertically disposed walls to provide a furnace chamber rectangular in cross-section. The chamber 10 has a roof 11 through which projects p one or more pulverized fuel burners 12, sup plied with fuel in the usual manner, the fuel eing projected downward and as it burns,

- the gases turn up and pass through the fursages 23 beneath it, the

nace exit at the right of the figure into entrance to the boiler, which, as shown, is a typical arrangement of a water tube boiler, the gases passing through the gas outlet flue 13 after passing back and forth across the water tubes in the well-known'manner.

The front wall 14: and the two opposite side walls of the furnace are provided with vertically disposed air passages, the passage or passages 15 in the front wall communicating through 0 nings 16 with the furnace chamher to supply air directly to the downcoming fuel. The side wall passages 17 are connected at the top to a common flue 18 from which the air passes to a fan 19 and from thence through a duct 20 to a duct 21 extending across the boiler and communicating with each of the burners 12.-

The furnace floor 22 has a passage or paspassage 23 communicatin with the lower ends of the passages 15 and 1 y The waste gases from the boiler pass through an air heater 24, and from thence to the smoke outlet 25, the air for the air heater entering through the duct 26 and, after passing back and forth over the heatin surface of the air heater, passes through the duct 27 to the passage 23, and from thence through the several vertically disposed air passages. it will be understood, of course, that a fan or other similar device may be used to force the air through the duct 26 and from.

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the

boiler circulation in the usual manner,

NEW JERSEY, ASSIGNOR,BY MZESNE AESIGNF- A CORPORATION OF DELAWARE a: coonnn summon 1925. Serial No- 85,958.

the side walls, is heated by the air heater,

so that'the difference in temperature between the inside and the outside of the wall is not so great as it would be if the air were not heated before entering the passage 23. This revents the two sides of the brickwork of the wall being subjected to great extremes in temperature. It will also be seen that the passage 23 serves not only to distribute the air from the duct 27 to the several vertical passages, bottom cooler than it otherwise would be. It will also be observed that heated air is delivered through the passage 15- directl into the furnace chamber, these passages 15 eing, intact, combustion air passages as well as wall-cooling passages. it will also be observed that the air flowing through the passages 17 will take up additional heat and that, therefore, the air supplied directly to the burners 12 will be hotter than the air supplied throu h the assages '16, By having the fan or ans 19 etween the wall-cooling passages and the burner, a minimum amount of air ressure need be ap lied to the passages 1 to force the air t rough them, so that the danger of leakage is minimized be cause of the relatively low pressure to which the passages 17 are subjected.

In the illustrative embodiment, I have shown the rear furnace wall cooled by a set of water tubes connected to slag screen tubes, all of these tubes being connected to the at since these are no part of my present inven-' tion, a detailed description thereof will be unnecessary. It will be understood, however, that, if desired, the rear wall may be cooled by passages 17 in the same manner as the side,

' walls are cooled.

but also serves to maintain the furnace widely varied. It will also be understood that the furnacemay be usedin any otherconnection than with a boiler and that it may be used with any kind of a, boiler. It will also be understood that while I have shown my invention in connection with a powdered fuel furnace, many of its features may be used with furnaces burning any other form of fuel. The various ducts may be supplied wit-h dampers, as desired, to regulate the flow of the air to the various parts.

I claim:

1. A furnacechamberhavingair passagesin the walls thereof, an air heater through which the furnace gases pass, a fuel burner to supply fuel to said chamber, ducts to lead heated air from said air heater to said passages and from thence to said burner, and a fan in the duct between said passages and said burner.

52. A furnace chamber having vertically disposed air passages in its walls, an air heater through which the furnace gases pass, a fuel burner to supply fuel to said chamber, ducts to lead heated air from said air heater to said passages and fromsaid passages to said burner, and a fan in the duct between said passages and said burner.

8. A furnace chamber having vertically disposed air passages in its walls, some of which passages communicate directly with said chamber, an air heater through which the furnace gases pass, a fuel burner to supply fuel to said chamber, ducts to lead heated air from said air heater to said passages, a duct to lead air from the upper part of said passages not directly communicating with said chamber to said burner, and a fan in said last-named duct.

4. A furnace chamber having vertically disposed air passages in the walls thereof, an air heater through whichthe furnace gases pass, ducts to lead heated air from said air heater to the lower part of said passages and from the upper part of said passages to the .urnace chamber and a fan located between said air assages and the furnace chamber.

5. A urnace chamber having vertically disposed air passages in the wallsthereof, a fuel burner to supply fuel to said chamber, an air heater through which the furnace gases pass,and ducts to lead heated air from the air heater to the lower part of said passages and from the upper partthereof to said burner.

6. A furnace chamber having verticall disposed air passages in the walls thereo air ducts beneath the furnace floor and communicating with the lower ends of said vertically disposed air passages, a pulverized fuel burner to supply fuel to said chamber,

anair heater through which the furnace gases 1 pass, and ducts to lead heated air fromvthe air heater to the ducts floor.

heating one of the parts beneath the furna 7. A furnace chamber having air p :e:

in the walls thereof, an air heater through which the furnace gases pass, ducts to lead heated air from said air heater to said passages, a fuel burner, means to supply heated air from said passages to said furnace chamber andmeans to' supply air from said passages at a higher temperature to said burner.

8. The method of operating a powdered fuel furnace comprising projecting a stream of the fuel into the furnace and ignitin the stream, supplying heated combustion air to the stream of burning fuel, heating additional combustion air to a temperature higher than that of the air supplied to the fuel stream, and supplying such additional com bustion air to the fuel as it enters the furnace.

9. The method of operating a powdered fuel furnace comprising projecting a stream of the fuel downwardly into the furnace and at one side thereof and igniting the stream, supplying heated combustion air to the downwardly moving stream of burning fuel and at different points along the stream, heating additional combustion air to a temperature higher than that of the air supplied to the fuel stream, and supplying such additional combustion air to the fuel as it enters the furmace.

10. The method of operating a powdered fuel furnace comprising projecting a stream of the fuel into the furnace and igniting the stream, dividing the total combustion air to be supplied to the furnace into two parts, heating one of the parts to a higher temperature than the other, mixin with the fuel as it enters t e furnace, and mixing the cooler air with the burning fuel in the furnace.

I 11. The method of operating a powdered fuel furnace comprising projecting a stream of the fuel into the furnace and igniting the stream, dividing the total combustion air to be supplied to the furnace into two parts, to a hi her tempera ture than the other, mixing t e hotter air with the fuel as it enters the furnace, mixing the cooler air with the burning fuelin the furnace, and delivering the hotter air under higher pressure than that of the cooler air.

DAVID S. J ACOBUS. 

